What is the Tensile Stress, Strain, and Young's Modulus of a Stretched Wire?

[h8torade]

Homework Statement

A load of 172 kg is supported by a wire of length 2.07m and cross-sectional area .143cm^2. The wire is stretched by 0.149 cm. Find tensile stress, strain, and Young's modulus.

Homework Equations

stress= F/A
strain= ∆L/L
E= stress/strain

The Attempt at a Solution

1685.6 N /.00143 m^2 = 1.17874e6 N/m^2 <---this one I need help with

.00149 m / 2.07 m = .00072 <--- I know this one is right

1.17874e6 N/m^2 / .00072 = 1.63758e9 N/m^2

 

[Pyrrhus]

0.143 cm2 to m2 is wrong. Remember it'll be 10^-4 m2.

 

[Doc Al]

1685.6 N /.00143 m^2 = 1.17874e6 N/m^2 <---this one I need help with

Careful with units: 1 cm^2 = (0.01m)^2 = 0.0001 m^2

 

[h8torade]

so the answer to the stress is 1685.6 N / .0000143 m^2 = 1.17874e8

which makes E = 1.63714e11